Vehicles may include a variety of airbags deployable during vehicle impacts to absorb energy from occupants of the vehicles during the impact. The airbag defines an inflation chamber, and an inflator is in communication with the inflation chamber for inflating the airbag from an uninflated position to an inflated position. One type of airbag is a knee airbag that is deployable below a steering column of the vehicle to absorb impact from the knees of a driver during a vehicle impact. The knee airbag may be supported by the instrument panel, e.g., behind a knee bolster, or may be supported by the steering column.
Vehicles are subject to a variety of impact tests. These impact tests may include those standardized by the Insurance Institute for Highway Safety (IIHS) and the National Highway Traffic and Safety Agency (NHTSA). These impact tests may include tests that urge occupants of the vehicle to move forward and sideways, for example, offset frontal impacts and oblique impact tests. One such test is the small overlap rigid barrier (SORB) test, in which a front corner of the vehicle is impacted with a rigid barrier that is offset from the centerline of the vehicle. In this test, the test dummy in the driver seat is urged forwardly and toward the impacted corner of the vehicle. Another type of impact test is an Oblique Impact Test, in which the vehicle is impacted at an angle relative to the centerline of the vehicle and the test dummy in the driver seat is urged forward and in a cross-vehicle direction toward the driver side door of the vehicle or toward the passenger side door of the vehicle.
During an impact that urges the occupant forward and sideways, the knees of the occupant may be urged to slide across the knee airbag toward a front corner of the vehicle. This sliding movement reduces the absorption of the impact force, and the knees of the occupant may slide off of the airbag and impact other components of the vehicle interior. Inflation of the airbag to a relatively high inflation pressure may encourage the knees of the occupant to slide during these types of impact. In addition, depending on various factors, the knee airbag may billow around the steering column, which may encourage the knees of the occupant to slide during impacts that urge the occupant to move forward and sideways.
There remains an opportunity to design a knee airbag that reduces the likelihood of the knees of the occupant from sliding across the knee airbag during impacts that urge the occupant to move in a forward and sideways direction.